Results from field trials conducted at test site in West Sussex. 

We’re delighted to reveal we’ve been working with one of the most successful science and engineering companies in the world, DuPont, to test a new membrane they have developed to control Japanese knotweed.

While it’s always preferable to remove Japanese knotweed entirely if possible, horizontal membranes laid beneath the surface of the ground can be useful in locations where it isn’t possible to remove or kill all the knotweed. This might be where underground services such as drainage and sewerage are present, or where a tree preservation order means the land cannot be disturbed.

DuPont approached us in 2017 with Plantex® Platinium, a new permeable membrane designed to control Japanese knotweed without causing problems with drainage. In the past impermeable membranes have been used, with the idea being that if water can’t get through then neither can knotweed, but they have been known to cause flooding and ground instability.

We conducted field trials of the new membrane during the 2017 growing season at our Japanese knotweed infested test site in West Sussex, which we purchased last year for Research and Development purposes.

To put the product under extreme test conditions, no attempt was made to remove any of the crowns or rhizomes before installing Plantex® Platinium, which was then covered with a minimum of 100mm clean topsoil and monitored from March to November for signs of knotweed growth.

No emergence was observed during this time, but new growth was seen around the periphery and was evident running horizontally beneath the membrane when it was lifted. This tells us that Plantex® Platinium is effective at controlling Japanese knotweed, even though it doesn’t kill it. We’re pleased to say this provides us with another string to our bow, enabling us to help clients who are not able to remove Japanese knotweed from their land and are seeking a compromise solution.

About the research, Carl Festré, DuPont EMEA Marketing Manager, Typar® and Plantex®, said: “We are happy with the results of the DuPont™ Plantex® Platinium test conducted by Environet in the fight against Japanese Knotweed.  These results confirm that Plantex® Platinium offers an effective, cost competitive and practical solution to control the spread of Japanese Knotweed.  As a manufacturer we will continue to look for opportunities to improve the product and the installation techniques to ensure full satisfaction of our customers.”

We look forward to carrying out further research in partnership with DuPont later this year.

To find out more about the research, please read or download our Beacon article here.